Technical Abstract:
Exposing a pregnant sow to stress has been shown to have negative effects on resulting offspring. However, little knowledge exists regarding the mechanisms of this process or the effects due to specific stressful events. In this study, sows received injections of ACTH (1 IU/kg BW) (ACTH, n=10), rough handling (ROU, n=11), or no treatment (CONT, n=6) once a week during d 35 to d 77 of gestation. At weaning animals were blocked for weight and sex after which ten groups of six pigs were formed with 2 pigs from each treatment group. Each group of six pigs was then placed in one of ten individual nursery pens. To assess the behavioral effects of treatments, all behaviors were recorded for 6 d post-weaning using video cameras mounted above each pen. Recorded video was then analyzed for duration, initiator, and recipient of each fight/play bout. To assess the effect of treatments on hematological cell profiles, blood was collected every other day for 10 d after weaning. Duration (pooled mean +/- SE; 25.9 +/- 1.7 s; p <.25) and interactions of fight/play bouts (p <.50) were similar regardless of treatment, though hematocrit and hemoglobin were greater (p <.04) in CONT pigs than the ACTH and ROU pigs. Our results suggest that pre-natal stress can influence the pig's physiological state during the post-weaning period. The effect of these parameters on the stress response during weaning and whether these treatment differences are maintained throughout the animal's lifetime remain important welfare issues and require investigation.